CN106396730B

CN106396730B - Preparation method of perlite heat insulation product

Info

Publication number: CN106396730B
Application number: CN201610766182.2A
Authority: CN
Inventors: 裘益奇; 裘茂法; 雷泉兴
Original assignee: Zhejiang Aske Building Materials Technology Corp
Current assignee: Zhejiang Aske Building Materials Technology Corp
Priority date: 2016-08-30
Filing date: 2016-08-30
Publication date: 2020-06-26
Anticipated expiration: 2036-08-30
Also published as: CN106396730A

Abstract

The invention discloses a preparation method of a perlite heat insulation product, which comprises the following steps: (a) selecting raw materials; (b) preparing materials; (c) pressing; (d) hardening and drying; (e) primary calcination; (f) mixing again; (g) secondary calcination; (h) and (6) packaging a finished product. The method has the advantages of short production period, simple operation, high controllability, low production cost, safety and effectiveness, and the prepared expanded perlite product has high compressive strength, low water absorption, good heat preservation, heat insulation and sound absorption properties, long service life and wide application range, and has a positive effect on building energy conservation.

Description

Preparation method of perlite heat insulation product

Technical Field

The invention belongs to the technical field of preparation of heat insulation materials, and particularly relates to a preparation method of a perlite heat insulation product.

Background

At present, most of external wall insulation boards for buildings are polystyrene boards, the external wall insulation material has the defects of easy aging, difficult degradation, serious environmental pollution, easy deformation, easy falling, short service life, poor fireproof performance, high construction difficulty, poor adhesion with the external wall of the building, high comprehensive cost and easy combustion, and the building fire caused by external wall insulation frequently occurs, so that the life and property safety of people is seriously threatened. At present, substitute products of polystyrene board heat insulation materials are developed in various places, mainly comprising perlite as a main heat insulation material, wherein the perlite has the characteristics of small apparent density, low heat conductivity coefficient, good chemical stability and wide use temperature range, and is widely applied to building external wall heat insulation systems.

The honeycomb-coal-shaped porous structure of the expanded perlite determines that the expanded perlite has good heat preservation and insulation effects, but the products have the biggest defects of low compressive strength and high water absorption rate, the compressive strength is generally between 0.4 and 1.1MPa, the water absorption rate is more than l1O percent, and the expanded perlite is easy to absorb moisture in the air due to environmental change, so that the products crack and the heat preservation and insulation effects are influenced. In fact, from the viewpoint of reducing the production cost, manufacturers often only have the strength higher than the minimum standard requirement, and the water absorption rate of the product is as high as more than 300%. These low strength, high water absorption expanded perlite products severely impact the areas of transportation, construction, durability, insulation and use.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art, and provides a preparation method of a perlite heat insulation product, which has the advantages of short production period, simple operation, high controllability, low production cost, safety and effectiveness, high compressive strength and low water absorption of the prepared expanded perlite product, good heat preservation, heat insulation and sound absorption properties, long service life and wide application range, and has a positive effect on building energy conservation.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of a perlite heat insulation product is characterized by comprising the following steps:

(a) selecting raw materials: the formula comprises the following components in parts by mass: 50-120 parts of 50-255 mesh expanded perlite, 4-10 parts of sodium silicate, 2-15 parts of dispersible latex powder, 6-20 parts of a water repellent, 50-120 parts of water, 10-20 parts of reinforcing fiber and 5-30 parts of an inorganic cementing material;

(b) preparing materials: placing the expanded perlite, the dispersible latex powder and the reinforced fiber in parts by mass in a stirring cylinder for mixing, uniformly stirring, simultaneously adding a mixture of sodium silicate, a water repellent and 25-60 parts of water into a stirring cylinder in a spraying manner, fully stirring the mixture to be mixed with the expanded perlite, the dispersible latex powder and the reinforced fiber into uniform mixture, adding 12-15% of additive based on the weight of the sodium silicate, controlling the rotating speed of the mixing drum to 300-350 r/m, stirring for 1-2.5 h at 30-35 deg.C, adding the mixture of sodium silicate, water repellent and water into a stirring cylinder in the form of spray, the contact area is increased, full mixing is facilitated, the reaction is complete, the utilization rate of raw materials is improved, and the additive is beneficial to reducing the melting temperature and viscosity of the sodium silicate, so that the later-stage calcining temperature is reduced, and the production cost is reduced;

(c) pressing: pressing the mixture into a green body by using a press after stirring, wherein the working parameter of the press is 6-10 MPa, the compression ratio is 1.5-2.2, the forming quality of the green body can be improved by reasonably controlling the compression ratio, and the loss can also be controlled;

(d) hardening and drying: drying the green body at room temperature for 1-1.5 h, and drying in a drying room at 70-100 ℃ for 10-12 h until the water content of the green body is less than 3.5%;

(e) primary calcination: placing the dried green body into a high-temperature furnace for calcining, heating the furnace body to 400 ℃ at the heating rate of 10-12 ℃/min, preheating the green body, adopting the heating rate of 6-8 ℃/min at the stage of 400-600 ℃, preserving heat for 1.5-2 h when the temperature of the furnace body is raised to 600-620 ℃, cooling the furnace body to 400-450 ℃ at the cooling rate of 15-20 ℃/min after heat preservation, observing the surface condition of the green body through a window of the high-temperature furnace during the cooling period, then entering the annealing stage, cooling the furnace body to the normal temperature at the cooling rate of 5-6 ℃/min, leading the surface of expanded perlite to be fused prematurely due to the excessive heating, leading the temperature difference between the inner layer and the outer layer of the mixture to be too large, leading the green body to be calcined unevenly, for example, the green body of a product is vitrified, and the green body is not sintered inside, and ensuring the uniform temperature inside, the sodium silicate can be fully melted, and the sodium silicate enters an annealing stage and is slowly cooled, so that the residual stress in the glass can be eliminated, and the blank body is ensured to have certain mechanical strength after being cooled;

(f) and (3) mixing again: crushing the cooled blank by using a crusher, mixing crushed blank powder, an inorganic cementing material and the rest water in a stirring cylinder, adding potassium iodide, stirring uniformly, wherein the adding amount of the potassium iodide is 15-25% of the weight of the inorganic cementing material, then filling the mixture into a mold, pressing the mixture by using a press, forming, airing in the air, taking the potassium iodide as a fluxing agent, wherein the adding amount of the potassium iodide has direct influence on the melting temperature of the inorganic cementing material, and within a reasonable adding amount range, the adding amount of the fluxing agent is increased, so that the melting temperature of the inorganic cementing material is reduced, therefore, the adding amount of the fluxing agent needs to be reasonably controlled, and the adding amount of the inorganic cementing material can improve the compressive strength of a final product and reduce the water absorption of the product;

(g) secondary calcination: placing the dried pressed product into a high-temperature furnace for roasting, heating the furnace body to 700 ℃ at a temperature rise speed of 20-25 ℃/min, wherein the roasting time is 1.5-2 h, and cooling at normal temperature after roasting is finished;

(h) packaging a finished product: and (4) measuring various standard parameters of the cooled product such as compressive strength, water absorption, bulk density and heat conductivity coefficient, and directly packaging qualified products for storage.

Further, in the step (c), the mixture is firstly filtered by a 8mm round-hole screen plate before being pressed, the sieved mixture is collected and pressed, and the screened screen plate can effectively prevent caking and has the function of secondary stirring.

Further, before the green body is placed into a drying room for drying in the step (d), the green body is placed into a vacuum tank, the vacuum tank is vacuumized to-0.1 MPa to-0.05 MPa, then the heating and drying are carried out, and the drying is carried out in a vacuum state, so that the drying speed is high, the drying time is greatly shortened, the possibility of side reaction between air and the green body is blocked, the collection of high-purity products is facilitated, the utilization rate of equipment is improved, and the economic benefit is improved.

Further, the modulus of the sodium silicate in the step (a) is 3.1-3.6, the density is more than or equal to 1.32, the sodium silicate is water glass which is light yellow viscous liquid and is alkaline, and the water glass can absorb CO in the air²Silica gel is generated, and the gel is dehydrated to become silica and is hardened, thereby playing a role of binding.

Further, the particle size of the expanded perlite in the step (a) is 0.6-1.3 mm, and the bulk density is 120-150 kg/m³Too high a bulk density of expanded perlite results in too low a thermal insulation performance.

Further, the fineness of the sodium silicate in the step (a) is 2500-3000 cm²The fineness of the sodium silicate affects the roasting temperature, the melting time is shorter when the fineness is finer, and the production cost is increased when the fineness of the sodium silicate is too fine, so that the fineness of the sodium silicate needs to be reasonably controlled and reducedAnd (5) the production cost.

Further, the fineness of the inorganic cementing material in the step (a) is more than 3000cm²The fineness of the inorganic cementing material influences the roasting temperature, when the content of alkali metal oxide in the inorganic cementing material is higher, the roasting temperature is lower, and if the fineness of the inorganic cementing material is too fine, the production cost can be increased, so that the fineness of the inorganic cementing material needs to be reasonably controlled, and the production cost is reduced.

Further, the pressing time of the press in the step (c) is 3-5 min.

Furthermore, the water repellent in the step (a) is dimethyl silicone oil which is nontoxic and tasteless, has the advantages of physiological inertia, good chemical stability, weather resistance and good hydrophobicity, and after mixing, the gaps of the expanded perlite are compact, so that the compression strength and the tensile strength of the expanded perlite are improved, and a permanent waterproof film is formed on the surface of the expanded perlite, so that the phenomena of expansion, deformation and falling are avoided.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

in the invention, the sodium silicate is changed into a molten state under the action of high temperature, and the addition of the additive is beneficial to reducing the melting temperature and viscosity of the sodium silicate, thereby reducing the later calcining temperature and reducing the production cost. The sodium silicate in a molten state flows into communicated pores among the expanded perlite, so that the water absorption of the expanded perlite is reduced, the dosage of the sodium silicate has an effect of increasing the compressive strength of the expanded perlite, and the compressive strength is increased when the dosage is more.

The inorganic cementing material is changed into a molten state under the action of high temperature, the viscosity of the melt is reduced due to the adding action of the fluxing agent, one part of the melt formed by the inorganic cementing material at high temperature is wrapped on the surface of the expanded perlite, the other part of the melt flows into the pores of the expanded perlite, after the melt is cooled, the dual functions of bonding and mechanical occlusion are formed, and meanwhile, the cooled melt forms a hard wrapping layer shell on the surface of the whole expanded perlite, so that the compressive strength of the expanded perlite is greatly improved, and the prepared expanded perlite product has high compressive strength.

The expanded perlite product prepared by the invention has the advantages of compression strength of more than or equal to 1.25MPa, water absorption of less than or equal to 70 percent, heat conductivity coefficient of 0.067-0.078W/(m.k), high compression strength, low water absorption, good heat preservation, heat insulation and sound absorption performances, long service life and positive effect on building energy conservation, can be used for heat insulation of civil building outer walls and roofs, can be widely applied to the fields of petroleum, chemical industry, underground engineering, national defense war industry and the like, and is a safe, reliable and durable building energy-saving environment-friendly material.

Drawings

The invention will be further described with reference to the accompanying drawings in which:

FIG. 1 is a schematic flow diagram of a method of making a perlite insulation product of the invention.

Detailed Description

As shown in FIG. 1, the preparation method of the perlite heat insulation product comprises the following steps:

(a) selecting raw materials: the formula comprises the following components in parts by mass: 50-120 parts of 50-255 mesh expanded perlite, and the expanded perlite with the optimal mesh number is selected, so that the quality of the final product is improved. The particle size of the expanded perlite is 0.6 mm-1.3 mm, and the bulk density is 120-150 kg/m³Too high a bulk density of expanded perlite results in too low a thermal insulation performance. 4-10 parts of sodium silicate, wherein the modulus of the sodium silicate is 3.1-3.6, the density is more than or equal to 1.32, the sodium silicate is water glass which is faint yellow viscous liquid and alkaline, and the water glass can absorb CO in the air²Silica gel is generated, and the gel is dehydrated to become silica and is hardened, thereby playing a role of binding. The fineness of the sodium silicate is 2500-3000 cm²The fineness of the sodium silicate affects the roasting temperature, the melting time is shorter when the fineness is finer, and the production cost is increased when the fineness of the sodium silicate is too fine, so that the fineness of the sodium silicate needs to be reasonably controlled, and the production cost is reduced.

2-15 parts of dispersible latex powder, wherein the dispersible latex powder has excellent waterproof performance and good bonding strength, the elasticity of the expanded perlite is increased after mixing, the opening time is prolonged, the alkali resistance of the expanded perlite is endowed, and the adhesion of the expanded perlite is improvedAdhesion, breaking strength, plasticity, wear resistance and workability, and plays a reinforcing role as a second binder. 6-20 parts of a water repellent, wherein the water repellent is simethicone which is non-toxic and odorless and has the advantages of physiological inertia, good chemical stability, weather resistance and good hydrophobicity, and gaps of the expanded perlite are compact after mixing, so that the compression strength and the tensile strength of the expanded perlite are improved, and a permanent waterproof film is formed on the surface of the expanded perlite, so that the phenomena of expansion, deformation and falling are avoided. 50-120 parts of water, 10-20 parts of reinforced fibers, inorganic fibers, stable and durable performance, acid and alkali resistance, ageing resistance, bacteria resistance and the like, and the prepared composite material has a very complex three-dimensional network structure with certain strength and toughness, so that the final product has excellent heat insulation performance and sound absorption and insulation performance. 5-30 parts of inorganic cementing material, wherein the inorganic cementing material is solid industrial waste, the production cost is low, and the fineness of the inorganic cementing material is more than 3000cm²The fineness of the inorganic cementing material influences the roasting temperature, when the content of alkali metal oxide in the inorganic cementing material is higher, the roasting temperature is lower, and if the fineness of the inorganic cementing material is too fine, the production cost can be increased, so that the fineness of the inorganic cementing material needs to be reasonably controlled, and the production cost is reduced.

(b) Preparing materials: placing the expanded perlite, the dispersible latex powder and the reinforcing fibers in the mixing drum in parts by mass for mixing, uniformly stirring, simultaneously adding a mixture of sodium silicate, the water repellent and 25-60 parts of water into the mixing drum in a spraying manner, fully stirring, mixing the mixture with the expanded perlite, the dispersible latex powder and the reinforcing fibers to form a uniform mixture, adding the mixture in a spraying manner, increasing the contact area, facilitating full mixing, completely reacting and improving the utilization rate of raw materials. Then adding an additive accounting for 12-15% of the weight of the sodium silicate, wherein the additive is beneficial to reducing the melting temperature and viscosity of the sodium silicate, thereby reducing the later calcining temperature and reducing the production cost. The rotating speed of the stirring cylinder is controlled to be 300-350 r/m, and the stirring time is 1-2.5 h at the temperature of 30-35 ℃.

(c) Pressing: after the stirring is finished, the mixture is filtered by the 8mm round-hole screen plate, the filtered mixture is collected and pressed, and the screened screen plate can effectively prevent caking and plays a role in secondary stirring. And pressing the mixture into a green body by using a press, wherein the working parameter of the press is 6-10 MPa, the pressing time is 3-5 min, the compression ratio is 1.5-2.2, the forming quality of the green body can be improved by reasonably controlling the compression ratio, and the loss can be controlled.

(d) Hardening and drying: the green body is firstly placed in a vacuum tank, the vacuum is pumped to-0.1 MPa to-0.05 MPa, then the heating and drying are carried out, the drying is carried out under the vacuum state, the drying speed is high, the drying time is greatly shortened, the possibility of side reaction between air and the green body is blocked, the collection of high-purity products is facilitated, the utilization rate of equipment is improved, and the economic benefit is improved. Drying the green body at room temperature for 1-1.5 h, and drying in a drying room at 70-100 deg.C for 10-12 h until the water content is less than 3.5%.

(e) Primary calcination: the dried green body is placed into a high-temperature furnace for calcination, the furnace body is heated to 400 ℃ at the heating rate of 10-12 ℃/min, the green body is preheated, the heating rate of 6-8 ℃/min is adopted at the stage of 400-600 ℃, too high heating rate can lead to premature melting of the surface of expanded perlite, the temperature difference between the inner layer and the outer layer of the mixture is too large, the green body is not calcined uniformly, for example, the phenomenon that the green body of a product is vitrified and the inside of the product is not sintered yet occurs, when the temperature of the furnace body is raised to 600-620 ℃, the heat is preserved for 1.5-2 h, the reasonable heat preservation time can ensure that the temperature inside and the outside of the green body is uniform, the heat preservation time is too short, the calcination is insufficient, the heat preservation time. After heat preservation, the furnace body is rapidly cooled to 400-450 ℃ at the cooling speed of 15-20 ℃/min, so as to avoid the glass melt which is uniformly melted on the surface of the expanded perlite from flowing. And during the cooling period, observing the surface condition of the blank through a window of the high-temperature furnace, and if the glass melt on the surface of the expanded perlite flows too much, accelerating the cooling speed. And then, in an annealing stage, cooling the furnace body to normal temperature at a cooling speed of 5-6 ℃/min, fully melting the sodium silicate, and in the annealing stage, slowly cooling to eliminate residual stress in the glass and ensure that the blank has certain mechanical strength after being cooled.

(f) And (3) mixing again: crushing the cooled blank by using a crusher, mixing the crushed blank powder, the inorganic cementing material and the rest water in a stirring cylinder, adding potassium iodide, stirring uniformly, wherein the adding amount of the potassium iodide is 20-25% of the weight of the inorganic cementing material, then filling the mixture into a mold, pressing the mixture by using a press, forming, airing in the air, taking the potassium iodide as a fluxing agent, wherein the adding amount of the potassium iodide has direct influence on the melting temperature of the inorganic cementing material, and within a reasonable adding amount range, the adding amount of the fluxing agent is increased, so that the melting temperature of the inorganic cementing material is reduced, therefore, the adding amount of the fluxing agent needs to be reasonably controlled, and the adding of the inorganic cementing material can improve the compressive strength of a final product and reduce the water absorption of the product. Table 1 shows the effect of potassium iodide dosage on the melting temperature of the inorganic cementitious material:

numbering	Weight ratio (cosolvent: inorganic cementing material)	Melting temperature (. degree.C.)
			1	0.1	812
2	0.15	755
			3	0.2	702
4	0.25	698
			5	0.3	694
6	0.35	691
			7	0.4	688

TABLE 1 influence of the amount of potassium iodide on the melting temperature of the inorganic cementitious materials

As can be seen from table 1, as the amount of potassium iodide is increased, the melting temperature of the inorganic cementing material is gradually decreased, and when the amount of potassium iodide is increased to a certain amount (20% to 30%), the decrease of the melting temperature is small, and from the viewpoint of energy consumption, the lower the melting temperature of the inorganic cementing material is, the better the melting temperature is, but the too low temperature inevitably causes the increase of the amount of potassium iodide, which leads to the increase of the production cost, so the amount of potassium iodide should be reasonably controlled, and is preferably 20% to 25% of the weight of the inorganic cementing material.

(g) Secondary calcination: and (3) roasting the dried pressed product in a high-temperature furnace, heating the furnace body to 700 ℃ at a temperature rise speed of 20-25 ℃/min, roasting for 1.5-2 h, and cooling at normal temperature after roasting is finished.

(h) Packaging a finished product: and (4) measuring various standard parameters of the cooled product such as compressive strength, water absorption, bulk density and heat conductivity coefficient, and directly packaging qualified products for storage. Table 2 shows the effect of different amounts of sodium silicate on the physical properties of the expanded perlite product:

table 2 shows the effect of different amounts of sodium silicate on the physical properties of expanded perlite

As can be seen from Table 2, with the increase of the usage amount of the sodium silicate, the water absorption rate of the expanded perlite product is gradually reduced, the compressive strength is gradually increased, the influence of the usage amount of the sodium silicate on the compressive strength of the expanded perlite product can be further studied, the heat conductivity coefficient is also gradually increased, but the increase is not large, which indicates that the usage amount of the sodium silicate has little influence on the heat conductivity of the product.

Table 3 shows the effect of different amounts of the inorganic binder on the physical properties of the expanded perlite product:

table 3 shows the effect of different amounts of the inorganic binder on the physical properties of the expanded perlite

As can be seen from Table 3, with the increase of the amount of the inorganic cementing material, the water absorption of the expanded perlite product is gradually reduced, and the compressive strength is gradually increased, and when the amount of the inorganic cementing material is 12% of that of the expanded perlite, the compressive strength is 0.63MPa, which has reached the minimum requirement (0.490 MPa for the superior product) of the similar products in the technical performance index of the expanded perlite heat insulation product of the Ministry of construction, thus expanding the application range of the expanded perlite product and achieving high economic benefit. The heat conductivity coefficient is gradually increased, but the increase of the heat conductivity coefficient is not large, which indicates that the use amount of the inorganic cementing material has little influence on the heat conductivity of the product.

The above is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions or modifications made based on the present invention to solve the same technical problems and achieve the same technical effects are within the scope of the present invention.

Claims

1. A preparation method of a perlite heat insulation product is characterized by comprising the following steps:

(b) preparing materials: placing the expanded perlite, the dispersible latex powder and the reinforcing fiber in parts by weight into a stirring cylinder, mixing and stirring uniformly, simultaneously adding a mixture of sodium silicate, a water repellent and 25-60 parts of water into the stirring cylinder in a spraying manner, fully stirring to mix the mixture with the expanded perlite, the dispersible latex powder and the reinforcing fiber into a uniform mixture, adding an additive accounting for 12-15% of the weight of the sodium silicate, controlling the rotation speed of the stirring cylinder to be 300-350 revolutions per minute, and stirring for 1-2.5 hours at 30-35 ℃;

(c) pressing: after stirring, firstly, the mixture is sieved by a round-hole sieve plate with the diameter of 8mm, the sieved mixture is collected, and the mixture is pressed into a green body by a press, wherein the working parameter of the press is 6-10 MPa, and the compression ratio is 1.5-2.2;

(e) primary calcination: placing the dried blank body into a high-temperature furnace for calcining, heating the furnace body to 400 ℃ at a heating rate of 10-12 ℃/min, preheating the blank body, keeping the temperature for 1.5-2 h at the temperature of 400-600 ℃ at a heating rate of 6-8 ℃/min, keeping the temperature when the temperature of the furnace body rises to 600-620 ℃, cooling the furnace body to 400-450 ℃ at a cooling rate of 15-20 ℃/min after keeping the temperature, observing the surface condition of the blank body through a window of the high-temperature furnace during cooling, and then entering an annealing stage, cooling the furnace body to normal temperature at a cooling rate of 5-6 ℃/min;

(f) and (3) mixing again: crushing the cooled green body by using a crusher, mixing the crushed green body powder, the inorganic cementing material and the rest water in a stirring cylinder, adding potassium iodide, stirring uniformly, wherein the adding amount of the potassium iodide is 15-25% of the weight of the inorganic cementing material, then filling the mixture into a mold, pressing the mixture by using a press, forming, and airing in the air;

2. The method of making a perlite thermal insulation product as defined in claim 1 wherein: before the green body is placed into a drying room for drying in the step (d), the green body is placed into a vacuum tank, the vacuum tank is vacuumized to-0.1 MPa-0.05 MPa, and then the heating and drying are carried out.

3. The method of making a perlite thermal insulation product as defined in claim 1 wherein: the modulus of the sodium silicate in the step (a) is 3.1-3.6, and the density is more than or equal to 1.32.

4. The method of making a perlite thermal insulation product as defined in claim 1 wherein: the particle size of the expanded perlite in the step (a) is 0.6-1.3 mm, and the bulk density is 120-150 kg/m³。

5. The method of making a perlite thermal insulation product as defined in claim 1 wherein: the fineness of the sodium silicate in the step (a) is 2500-3000 cm²/g。

6. The method of making a perlite thermal insulation product as defined in claim 1 wherein: the fineness of the inorganic cementing material in the step (a) is more than 3000cm²/g。

7. The method of making a perlite thermal insulation product as defined in claim 1 wherein: and (c) the pressing time of the pressing machine in the step (c) is 3-5 min.

8. The method of making a perlite thermal insulation product as defined in claim 1 wherein: the water repellent in the step (a) is dimethyl silicone oil.